Practice30Create account

Find the values of for which has equal roots.

Class 10Quadratic EquationsAlgebra — Quadratics
  • A−1 and −4
  • B1 and −4
  • C1 and 4
  • D2 and 3

Step-by-Step Solution

Here , so → → → → . Check ; check — both perfect squares. The negative options come from mis-signing the middle term of ; "2 and 3" has the wrong sum and product.
Answer: C) 1 and 4

Key idea: The discriminant — nature of roots

classifies the roots of **: TWO distinct real roots. Parabola crosses -axis at two points.
- ****: ONE repeated real root (called a 'double root' or 'two equal roots'). Parabola touches -axis at the vertex.
- ****: NO real roots. Parabola does not touch the -axis at all.

**Use case**: 'For what values of does have equal roots?' → set → .

You can answer 'how many real roots?' WITHOUT computing them — just compute .

Master this chapter in 30 minutes a day.

Don't just memorise the answer — build a daily practice habit.

Practice 5 Similar Questions Free →

All Quadratic Equations practice questions

More Class 10 Quadratic Equations practice

For which values of k does 3x² + 2x + k = 0 have two distinct real roots?The equation x² − 2x + k = 0 has real roots. What is the largest value k can take?A quadratic equation has roots 2/3 and −4. After clearing all fractions, which equation…α and β are the roots of x² − 9x + 14 = 0. Find the equation whose roots are 2α and 2β.The two roots of a quadratic equation are equal in size but opposite in sign, and their…